Figure 1 depicts a strain gauge load cell. In response to changes in load on the device, the resistance of the strain gauge changes proportionally.

Figure 2 depicts a spring combined with a linear potentiometer. As we know from Hooke's law the displacement of a spring from its resting length corresponds linearly to the load applied to it. Is this a load cell?

Figure 3 depicts a spring combined with a rotational potentiometer by means of a lever and a pair of gears. Is this a load cell?